GUI: Ask user to unlock wallet before signing psbt

src/qt/psbtoperationsdialog.cpp

@@ -71,6 +71,9 @@ void PSBTOperationsDialog::signTransaction()
 {
     bool complete;
     size_t n_signed;
+
+    WalletModel::UnlockContext ctx(m_wallet_model->requestUnlock());
+
     TransactionError err = m_wallet_model->wallet().fillPSBT(SIGHASH_ALL, true /* sign */, true /* bip32derivs */, &n_signed, m_transaction_data, complete);
 
     if (err != TransactionError::OK) {
@@ -81,7 +84,9 @@ void PSBTOperationsDialog::signTransaction()
 
     updateTransactionDisplay();
 
-    if (!complete && n_signed < 1) {
+    if (!complete && !ctx.isValid()) {
+        showStatus(tr("Cannot sign inputs while wallet is locked."), StatusLevel::WARN);
+    } else if (!complete && n_signed < 1) {
         showStatus(tr("Could not sign any more inputs."), StatusLevel::WARN);
     } else if (!complete) {
         showStatus(tr("Signed %1 inputs, but more signatures are still required.").arg(n_signed),